Smooth rolling cars

Discussion in 'FAQs' started by nosweat, Jan 18, 2008.

  1. nosweat

    nosweat New Member

    I have been doing some long overdue maintenance on my rolling stock. I have noticed wide variability in how well individual cars roll - some seem to go forever with a small push, others barely glide a few inches. Is there any standard for measuring this? For example, suppose an 8" piece of track is raised 1" at one end and the amount of glide on a level flex track is then measured. Or are there some rough rules of thumb on when one should seriously think about replacing the wheels, or trucks, or both?

    I would appreciate any comments or suggestions.
  2. pgandw

    pgandw Active Member

    How consistent and free rolling your trucks need to be depends on how sharp your curves are, how steep your grades are, and most importantly, how long your trains are.

    It sounds like you are in N scale. To avoid stringlining with long trains, a decent curve radius and reasonably free-rolling cars are critical.

    Cars should roll freely down a less than 2% grade - which is the end of an 8" piece of track raised about 5/32". Or raise the end of the 8" track 1/8" which gives you a 1.6% grade. Any car which will not roll down the grade by itself isn't free-rolling enough and/or is too light. Very free-rolling cars will roll on less than a .75% grade - the end of your 8" track raised 1/16"!

    The above would be my recommendations. Being in HO/HOn3 myself, I test with a 24" piece of track with the end raised 1/2" above level, which is close to a 2.1% grade.

    Higher friction, especially in N, will significantly the number of cars your engine can pull.

    The disadvantage of free rolling cars is the Kadee/MicroTrains coupling "dance" and "slinky effect". Light cars that are very free rolling are difficult to couple when pushed together. The scissors and spring design of HOn3 and N couplers can give a longer train of free rolling cars a "slinky" look as cars move closer together and further apart as they roll along.

    my thoughts, your choices
  3. 60103

    60103 Pooh Bah

    I like cars to roll down a 2% grade. Luckily, I built one on my layout right where it is handy. I put cars at the top and expect they will roll down the grade without a push. I also use it to compare cars - which will roll farthest and which will catch up with another.
    Too free-rolling is a problem sometimes. Steel axles can cause them to bunch and uncouple over magnets. I stopped one train in a high-level yard and uncoupled the caboose; the caboose rolled down the grade, around the helix and into the previous station.
  4. nosweat

    nosweat New Member

    Thank you

    I am in HO.

    I just checked the stuff I have lying around and noticed that Woodland Scenics Subterrain incline sets provide a 2% grade.

    I just tried this with the 3 boxcars I was working on today. One rolled easily, one would roll for a bit with a gentle push, and one would not roll even with a push. I will begin with the last one.

    First I will try replacing the wheels, but if that doesn't help then I will replace the trucks, and maybe both.

    I appreciate the comments about the problems if the cars roll too easily. I hadn't thought of that!

    I assume that tables on the recommended weight for cars may also make a difference.

    Once again, your feedback has been a great help.
  5. 60103

    60103 Pooh Bah

    With the problem cars, there are a few things to try before you start spending money.
    If the truck is metal with springs, make sure the side frames are vertical and parallel and straight,
    Take the axles out and check the ends. They should have sharp points. Clean any debris off the ends and also out of the axle boxes. If the points are other than sharp, you may have to start spending. There may be burrs on the end or it may be bent over. Replace, then consider machining it.
    If the axle if tight in plastic side frames, a gentle squeeze may settle the axle ends in better. You should get a free spin when you flick the wheel with your finger.
    There is a tool that shapes axle boxes to take axle ends.
    And axle lengths vary. Manufacturers often make them a bit sloppy because they run better.

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